The conventional wiper is constructed and installed outside the windshield of a car. During rainy or cold weather, the car doors are always closed to prevent the penetration of outside cold or moisture air. The air within the car will then be affected without flow. The exhausted carbon dioxide gas from human body, the moisture or the contaminated air will accumulate at the windshield which will then obstruct the driver's sight and can easily cause a traffic accident. The present inventors have addressed themselves to this problem and set forth the present invention which provides for both interior and outer wipers so as to clear the driver's line of vision and thus enhance traffic safety.